In the early history of pneumatic automobile tires there have been numerous designs for valve stem covers, as illustrated in the following U.S. patents:
U.S. Pat. No. 1,792,659 to Schweinert PA1 U.S. Pat. No. 1,631,050 to Murphy PA1 U.S. Pat. No. 1,498,294 to Preston PA1 U.S. Pat. No. 1,326,455 to Kautzman.
All of these prior art valve stem covers involved rigid metal stems utilized with an inner-tube type tire. With the recent advent of tubeless tires, a rubber valve stem has evolved which carries a conventional air valve in its threaded outer end. These rubber stems are vulnerable to various sharp objects which they may come into contact with. While these valve stems do have small caps which merely protect the interior valve and its threaded end, the basic rubber stem has been left exposed to the elements along with other road hazards. A rubber valve stem of this type requires a substantial amount of resiliency so that it may seal in the rim opening as the stem is pulled into place. An exposed rubber valve stem becomes stiff and deteriorates due not only to the exposure to the sun but also contact with various salts, oils and other road-related substances.